1. Field of the Invention
The present invention relates to modular fireplace systems and, more particularly, to a modular fireplace construction that increases the energy and drafting efficiency of the modular fireplace.
2. Background Art
The invention relates to a modular fireplace construction for application in a commercial setting or in a residential dwelling. Modular fireplace construction of an open-type fireplace in residential construction is well known. The advantage of modular fireplace construction and insulation are primary in the reduced cost of the precast fireplace sections which can be molded into small and light pieces that assemble quickly when compared to brick and masonry construction. There is also a cost savings realized through reduced labor required for construction as only one or two people may be required to move in place the lighter fireplace sections and there is no requirement for a highly paid and highly skilled masonry workers.
The following U.S. patents describe various types of modular open-fireplace construction, these include U.S. Pat. No. 5,186,161 to Schumack; U.S. Pat. No. 4,686,807 to Newsome; U.S. Pat. No. 4,984,562 to Peterson, et al.; U.S. Pat. No. 4,478,208 to Pitha; and U.S. Pat. No. 1,069,944 to Hacker. While the above-mentioned prior art modular fireplaces have an advantage over free-built structures in terms of cost savings both in material and labor, the prior art modular fireplaces are typically difficult to assemble because the individual sections are not easy to handle and many pieces appear almost identical. Additionally, the above-mentioned modular fireplaces have one constant failing, that is, they sacrifice the heating and drafting efficiency of the modular fireplace due to limitations imposed by the requirement to use simply constructed modular segments for the "ease of construction." The self imposed limitation in prior art modular fireplace designs thus fails to remove efficiently the smoke.
The design and construction of an efficient, functional fireplace requires adherence to some basic rules concerning dimensions and the placement of various component parts. The objectives of a correctly designed fireplace are to: (1) assure proper combustion of the fuel; (2) deliver smoke and other products of combustion up the chimney; (3) radiate the maximum amount of heat into the room; and (4) afford simplicity and fire safety in construction. One of the best fireplaces, to keep warm with minimum consumption of wood fuel, was developed over two hundred years ago after countless generations of heating with wood and is known as a Rumford fireplace. Count Rumford achieved the objectives of a correctly designed fireplace by designing his fireplace around four basic principles: bum the fire hot and fast in a shallow firebox, channel the hot flu gases through a mass of masonry designed to absorb the heat, radiate as much heat energy from the masonry mass as possible, and increase the efficiency of the draw of the fireplace. The hotter the fire, the more efficient this conversion process becomes, and the more stored energy in the wood is converted into heat. When the hot flu gases are then channeled through several tons of masonry, through properly designed flu passages, most of this heat can be absorbed and stored by the masonry. Stored heat will then be radiated to adjacent living space over a period of many hours.
The fireplace must both contain the fire and draw the smoke up through the chimney to the outside. Efficiency in removing the smoke is of prime importance and the dimensional ratios among the size of the firebox area, the smoke chamber, and the chimney flue will directly affect the efficiency of the fireplace if any of the ratios are improper. Other factors which affect the efficiency of the drawing ability of a fireplace are atmospheric conditions and the materials used. For example, a fireplace that drafts well at sea level may not draft as well at a higher altitude due to lower barometric pressure. Likewise, a fireplace constructed all or in part of metal will be a colder fireplace than one made of a refractory ceramic or cement, and will draft less efficiently.
Modular fireplaces, although more expensive than the various metal fireplace units that have been used by builders to facilitate fireplace construction, provide heating efficiency and safety improvements over the prior art metal fireplace units. A metal fireplace provides a functionally effective design form that is easily surrounded by masonry, faced with masonry veneer, and surrounded by a chimney. Highly skilled masons knowledgeable in fireplace construction are not needed and much of the guess work is eliminated from the construction of masonry fireplaces. Unfortunately, metal fireplaces are typically not durable, and depending on climatic conditions and the nature of the wood burned therein, rarely last as long as 25 years, and generally fail on average within 7 to 10 years. When a metal firebox fails, it typically results in metal corrosion around the point of failure which makes the metal fireplace a safety hazard and not useful until the defect is corrected. Repairing this defect is a very expensive procedure. A metal fireplace also lacks the masonry mass that allows the modular fireplace to efficiently store and radiate the heat energy of the fire and, as stated above, can result in problems due to inadequate drawing, which are especially aggravated in high altitude or multi-story applications.
Consequently, there exists a need in the art for a fireplace, such as a modular fireplace construction, that is structurally integrated to provide a substantially smoke leak-proof seal through the joints of the modular fireplace, while efficiently radiating heat into the adjoining space. Further there is a need in the art for a modular fireplace that increases the efficiency of the draw of the fireplace to allow for the proper combustion of the fuel and the efficient delivery of smoke and other products of combustion up the chimney while also providing ease of construction, enhanced fire safety and life expectancy of the fireplace construction.